Diablo, 4 piece tile and stone carbide tipped drill bit set Set consists of 18, 316, 14 and 516 drill bits Diablo’s tile and stone carbide tipped drill bit range provides faster starts and longer life in tile, stone and glass Optimized with a unique brazing and hardening process, the carbide tip extends life and productivity, allowing users to drill fast, accurate holes The multiground carbide tip design allows for aggressive starts that produce clean holes when drilling into hard materials The 3flat shank provides extra stability by eliminating spinning in the drill chuck